• 드라이브 ㆍ 컨트롤
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• 제15권3호
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• pp.43-48
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• 2018

The hydraulic control valve, used in the CPB (cold-pad-Batch) cold dyeing system, passes through a pressurized material that absorbs the dye. The hydraulic control of the hydraulic control panel shall be driven in a uniform and precisely controlled manner, as it interferes directly with the dyschromatism. In this study, an acceleration test model was employed to verify the durability of the hydraulic control of the hydraulic control panel, which was manufactured by the scenic model, and the pre-roll angle was analyzed before the performance of acceleration test. Based on the change in the amount of deformation of the padder roll the durability of the padder roll was analyzed along with verification of the durability of the skin and the rubber coating in contact with the fabric. Furthermore, the accelerated test method used for hydraulic controlled multi-cell padder rolls was verified.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.562-563
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• 2005

In case of aged porcelain, the failure in basic performance tests happened in cool-heat tests. Based on this characteristic, we studied the method predicting failure phenomena through more severe accelerated cool-heat ageing and accelerating thermal mechanical performance tests. Test results indicated that the thermal stress by temperature gradient was more severe parameter than thermal stress by quenching cycles within a category of standard or accelerating methods. And there is no the deterioration of statistic strength, but the deterioration of strength according to accelerating tests is serious.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 추계학술대회 논문집
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• pp.258-261
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• 1997

The sealing integrity is related to the safe operation of arrester the prime failure reason of porcelain housed arresters is moisture ingress. To be a meaningful tests a polymer arrester sealing test must be a realistic acceleration of field service. We think the test should be an accelerating course of actual temperatures, the enduring property to mechanical load and temperatures should be considered together. A union test method consisting of the thermal mechanical test and thermal cycling test is proposed to test the sealing integrity of polymeric arresters, which uses dielectric loss, leakage current 1mA DC voltage and partial discharge as the diagnostic techniques, and the test results were presented. The comparison states that the TMTCUT method is suitable fur the test of sealing integrity of polymeric arresters. .

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2004년도 정기학술대회
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• pp.221-226
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• 2004

The thermal stresses induced by difference in Coefficient of Thermal Expansion between FR-4 board and 63Sn-37Pb solder joint directly affect the reliability of 63Sn-37Pb solder joint. This research, thus, focuses to investigate the crack initiation and propagation behavior around solder joint by imposing a designed Acceleration Life Test Procedure on solder joint by using a newly manufactured Thermal Impact Experimental Apparatus. The fracture mechanism of the solder joint was found to be highly influenced by thermal stresses. The reliability of solder joint was evaluated by using a failure probability model in terms of varying parameters such as frequency and temperature. The relationship between failure probability and safety factor was also studied.

• 한국생산제조학회지
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• 제26권1호
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• pp.82-88
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• 2017

In 2016, a handmade vehicle called to the VF-3 was designed and manufactured as a formula typed car. Prior to manufacturing and assembly, the impact attenuator was analyzed through ANSYS LS-DYNA, and the results were applied to the VF-3. The dynamical performance of the VF-3, such as the acceleration and circling simulations, was also assessed through MSC-ADAMS. The results were applied and compared after the Korean Society of Automotive Engineers (KSAE) competition. There was only a 0.8 s difference in the acceleration test. In order that the frame was not twisted by thermal deformation, Argon-TIG welding was used and a zig was designed. Another zig was designed to have the exact position for the hardpoints in the suspension system. Most of the parts were made with aluminum 7050 for reduced weight. The VF-3 won the third prize in the 2016 KSAE Student Handmade Vehicle competition.

• 마이크로전자및패키징학회지
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• 제17권4호
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• pp.19-26
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• 2010

포화 수증기압이 고출력 형광체 변환 백색 LED 패키지의 열화현상에 미치는 주요 스트레스 인자임을 확인하였다. 또한 LED 패키지의 가속 수명시험을 통하여 포화 수증기압이 효과적인 가속 스트레스 인자임을 확인하였다. 실험조건은 350 mA 전류를 인가한 것과 인가하지 않은 2가지 조건에 대해 $121^{\circ}C$, 100% R.H. 환경에서 최대 168 시간동안 진행하였다. 실험결과 두 실험 모두 광 출력 감소, 스펙트럼 세기의 감소, 누설전류 및 열 저항이 증가하였다. 고장분석 결과 광 특성의 열화는 봉지재의 변색과 기포에 의해 발생한 것으로 나타났다. LED 패키지의 변색과 흡습에 의해 유발되는 기계적 (hygro-mechanical) 스트레스에 의한 기포 발생은 패키지 열화의 중요한 인자로써, 포화 수증기압이 고출력 LED의 수명시험 시간을 단축하기 위한 스트레스 인자로 적합함을 알 수 있었다.

• 대한기계학회논문집B
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• 제25권9호
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• pp.1193-1200
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• 2001

There are many regulation test methods to be related with engine emissions such as CVS-75, D-13, ECE-15 modes and so on. Most of these modes are consisted of lots of transient conditions that have rapid acceleration, deceleration and cranking modes. In this experimental research, the engine characteristics of cranking, accelerating and power output in a S.I. engine were studied to compare with neat gasoline and alternative fuels of M30 (methanol 30%, aromatic series 32%, non-aromatic 38%) and M50 (methanol 50%, aromatic 30%, non-aromatic 20%) for performance and exhaust emissions. The results show that reformulated methanol fuels are better emissions reduction of 15.7% over than that of neat gasoline fuel especially in HC and CO emissions at cranking mode. And the accelerating performances coincide with the results of distillation curve. CO concentration for M50 fuel is varied in a just little for the condition of slow acceleration. At wide-open throttle condition, brake specific energy consumption of reformulated fuels is increased and thermal efficiency is some what lower than that of gasoline fuel.

• Advanced Composite Materials
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• 제16권4호
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• pp.283-298
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• 2007

Environment-friendly composites reinforced with bagasse fiber (BF), a kind of natural fiber as the remains from squeezed sugarcane, were fabricated by injection molding and press molding. As appropriate matrices for injection molding and press molding, polypropylene (PP) and polycaprolactone-cornstarch (PCL-C) were selected, as a typical recyclable resin and biodegradable resin, respectively. The mechanical properties of BF/PP composites were investigated in view of fiber mass fraction and injection molding conditions. And the mechanical properties and the biodegradation of BF/PCL composites were also evaluated. In the case of injection molding, the flexural modulus increased with an increase in fiber mass fraction, and the mechanical properties decreased with an increase in cylinder temperature due to the thermal degradation of BF. The optimum conditions increasing the flexural properties and the impact strength were $90^{\circ}C$ mold temperature, 30 s injection interval, and in the range of 165 to $185^{\circ}C$ cylinder temperature. On the other hand, as to BF/PCL-C fully-green composites, both the flexural properties and the impact strength increased with an increase in fiber mass fraction. It is considered that the BF compressed during preparation could result in the enhancement in mechanical properties. The results of the biodegradability test showed the addition of BF caused the acceleration of weight loss, which increased further with increasing fiber content. This reveals that the addition and the quantities of BF could promote the biodegradation of fully-green composites.

• 한국항공우주학회지
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• 제32권9호
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• pp.103-113
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• 2004

위성은 조립 및 시험 완료 후 운반 및 발사 순간부터 임무 궤도로 진입할 때까지 발사체에 의한 정하중, 동하중 및 충격하중을 겪게 되며, 임무궤도에서 열진공, 복사 및 미세중력 환경하에 놓이게 되어 위성의 설계, 제작, 조립 및 시험 시 이들 발사환경과 우주환경을 고려하여 개발을 수행하여야 한다. 본 논문에서는 HAUSAT-1 피코위성의 구조 열해석과 설계 결과를 논의하고, 발사 과정과 우주에서 겪게 되는 환경을 모사한 발사환경 및 우주환경시험의 결과를 논의한다. HAUSAT-1 위성의 기계시스템은 인증 수준의 진동시험과 열진공시험 후에도 안정하다는 것을 확인하였다.

• 대한기계학회논문집A
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• 제39권9호
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• pp.831-837
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• 2015

사람과 전자기기들은 우리 주변의 환경 속, 특히 병원의 자기 공명 영상(Magnetic resonance imaging, MRI) 장비 또는 군용으로 사용되는 전자기 펄스(Electromagnetic pulse, EMP) 장비, 그리고 수많은 전자파를 만들어 내는 장치들에 노출되는 경우가 잦아졌다. 이러한 전자파는 사람과 전자기기에 유해하고, 이를 차폐하기 위해 사용되는 것 중에 하나가 핑거 스트립이다. 핑거 스트립은 열전도성이 좋기 때문에 전자파를 흡수하여 열로 변환한다. 이 특징을 효과적으로 이용하여 전자파 차폐가 필요한 실내의 특수 문짝에 핑거 스트립을 설치해서, 전자파로부터 사람과 전자기기들을 보호한다. 본 연구에서는 핑거 스트립의 주 고장모드에 영향을 주는 가속인자로 하중을 선택하여 가속수명시험을 실시한다. 가속수명시험의 결과로부터 핑거 스트립의 실사용조건 수명을 예측하며, 동일한 조건에서 실시한 수명 시험 결과와 비교하여 가속수명시험의 유효성을 평가하고자 하였다.